Telephone system



C. W. KECKLER.

TELEPHONE SYSTEM. APPLICATION man MAY 24, 1917.

Patented Mar. 16, 1920.

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COMIfANY, rnconronarnp, ornnwpironx; Na a eon'ronn'rion on NEW YORK.

i Sneciiicati on ILiLf trSiPQtc tQ if Patent'ed Bla r .16, 1920.

Application man-a 24, 917 Serial1\To.u1'7'0,602;

Torall whom it may concern; V

V Be it known that I, OHAnLnsWrKnoKLnn,

a citizen oftlie United States, ures idi'ngat NewarlqinthecountyofEssexand Stateof New Jersey, have invented. certain new anduseful Improvements in'Telephone Systems,

' of which the-following isa full, clear, concise,"- andfexactdescription.

- .tems in whicha plurality .o'f telephone -sta- This invention relatesto telephone, systems, and more particularly to such sys- ,tions obtainservicefover a'single line cir:

I j A The objectof this invention isto enable a subscriber atone of thestations when; the receiver is removed from the s'wltchhook to obtain aclear circuit to the centraloflice which is free from:interruptiOnsfrOrfi 7 any a of the subscribers at the other in'accessto this line.

" in accordancepwithia feature-of this in-1 station's hav- I vention, a;5 pluralit [of stations j norinally "disconnected'ifromajl neicircultareeach provided with a relay kWllIQh, when; .ener

; hectedwith the lineicircuit. 1 I g 'fflhisinvention isiIIustratedinthe cuit comprising line conductors 5 and 61ex- V linecireuit, two suchstations, B and C,

thexgswitchhook while one station is con- 7 "accompanying drawing, inwhlch'a line cirtends from a central ofiice A. A plurality ofsubscribers"'stations'have access to this being shown in-the drawing.Individual to each 'statlon 1's a'relay'7, which, when energized, 1sadapted to connect its associated station 'Withthe line circuit. -.-Forpurpose ,cof identification the individual relay of station B will behereinafter referred to as "7B 1' and that for station G. as 7C. A relay8,

common to the" line circuit, operates upon the energization of any oneof the individual' relays 7 to prevent the operation of all otherindividual relays. A relay 9 of high resistance controlling thevibrating contact, together with a source of current,

serves asfa sourceoftone signaling current which, on account iof 1 th'eiback contact of crimes or mw mmw annsnit, nssrenoe,ro'j wnsrnnnnmcrnrcrelay 8- beingnormally closed, is normally of relay v8, when energized,maintains a locking and holding circuit for any 'indi vidual. relaywhich may he energized.

Referring to the operation of the system I disclosed in the 'dr'awing,it will be assumed 'thatthesubscriberof station B initiates a -;call by.removing the receiver *from the switch-hook,whereupon relay, 7B "is enelgized over a circuit from battery through the normal contact of relay8," upper wind.-

'disablecl ,fb,ut is reiidered-eifective upon the I 7 operation of relay8 to provide a busy test. Aslow-releasing relay 10 under the control mgof -relay FB,contact ;thereof, -the switchhook contact and apparatus atstation'-B, and con'tact'16 of relay 7 B to ground!- Relay '7B," in;operating, establishes a loclr ing andhold-ingl circuit through itslower winding, whicli'may be traced from battery through;contaot il'l:of- :slow-releasing relay 10; lowe'rwvinding .of relay 17B ,"and contact18 or relay 7 B to -'ground-.- F Upon the operration OfreIay-WB,relaySisOperated over a v a circuit ,from' battery QO-atthecentral'oflice Cir A,throughthei vinding ofrelay 8,1inecond-uctor :5,contact 21- :of Y relay 7 B, switch ihook contactf andapparatusatstation B, contact'22 of relay 7B," and: line conductor 6' back to thebattery f Relay-7 8, in operati11g,:opens its-normal contact, therebydisabling the 7' individual "relays ofall' other j stations whichhaveaccessto this line cir- 1 'cuit; This'isaccomplishedgby opening thef V original energizing circuit, which is common to all of theindividualrelaysjat the nor mal contact of relay'8, and inserting inthis originalenergizing circuit the high resistance winding of relay 9; Theresistance of the winding'of this'relay 9 is'soahigh' as to prevent theoperation of'any' of theother individual relays shouldthe'receiver ofthe station r' tssociated' therewitlrbe removed y from its switchhookwhile individual relay 9 is'in the circuit, Upon the operation ofrelay'8,fslow-releasing relay; 10 also operates,transferring the lockingand holding circuit for relay 7B from the normal contactv '17 of relay10' to the alternate contact thereof and the alternate contact of relay8. In operating its'normal contact, relay ,8 there'- j by removestheshort circuit from relay 9 so that should the receiver at any of thesoff stations for exam ale station C be removed from its switchhookwhile station B is connected to theline circuit, relay 9 would beintermittently operated over a circuit from battery throughthe windingof, relay 9, the vibrating contact thereof, conductor 23, the upperwindings of relay 7C, and upper normal contact. thereof, through the'switchl'iooltcontact and primary of the in duction coil at station Cand the lower normal contact of relay 7G to ground. The intermittentopening and closing of this circuit, due to-the opening'and closing ofthe vib'ating contactofrelay 9, causes a current to be induced tosecondary winding of the ll'itlllCtlOIl coil at station C, whereuponatone 1s produced 111 the receiver at station C indicating that the lineci-rcuitis When the receiver at station E is restored to the switchhook,relay 8 releases, thereby opening a locking circuit for relay 7B.,whichnew releases. Upon the release of relay 8,

the slow-releasing relay 10 is also dee'nergized, whereby all apparatusis inits normal position, ready for actuation by any other stationhaving access to this line. i hat is claimed is: r V 1. In a telephonesystem, line conductors,

a plurality of subscribers stationsnormally disconnected from the line"conductors, cirs cuit leads for extending the line conductors to thesubscribers station, {a switch for; brldging the telephonic apparatusacross the circuit leads, a relay individual toeach station servingwhenenergized to complete the connection between the circuit leads and theline conductors, an energizingcircuit for the individual relayincluding-a portion of the circuit leads and establishedupon theactuation of the switch, alocking circuit for the individual relaycompleted upon the energization thereof, and a common relay controlledover the line conductors by themdiridual relay to disable the energizingcirdisable all other individual relays while the y one of saidindividual relays remains energiz'ed, and a normally disabled source oftone signaling current rendered effective and as sociated with all otherstations upon the operationof the common relay.

', 3. A telephone exchange system, comprising line conductors, aplurality of subscribers stations normally disconnected from the lineconductors, a relay individual to each station serving when energized toconnect I the station to the line conductors, a second relay common tothe line conductors, an ei'iergizing circuit therefor established overacircuit including the subscribers station said relay adapted whenenergized to disable all other individual relays while the one of saidindividual relays remains energized, and a normally disabled source'oftone sig naling currentrendered effective and associatedwith all otherstations upon-the operation of the common relay.

l. In a telephone system, line conductors, a plurality of subscribersstationsnormally disconnected from the line conductors, a relayindividual to each station serving when energized to connect the stationto the line conductors, a relay common to the line conductors andoperating over a circuitincluding the subscribers station upon theclosure of thelline conductors thereat,and a disabling circuit renderedefi'ective upon the operation'ot said common relay to prevent theenergization-ofall other individual relays while the'one or saidindividual relays re mains energized. r

5. In a telephone system,,line conductors,

a plurality otsubscribers stations normally disconnected from the lineconductors, a

relay individual to e-ach station serving when energized to connect thestation to the line conductors, a relay common to the, line con ductorsand operating over a circuit includinga subscribers station upon theclosure of the line conductors thereaaa disabling circuit renderedeffective upon the operation of said common; relay to prevent'theenergization of all other individual relays while one of saidindividualrelays remains energized, and a normally, disabled source oftone-signaling current rendered eilectiveand associated "with all otherstations upon :the operation of the common relay;

In-witness whereof I hereunto subscribe myname this 22nd day of May, A.D. 1917.

CHARLES W. KECKLER. I

